I recently watched Starship Troopers for the first time. It’s brilliant, isn’t it? I can’t believe I’d never seen it before.

If you can set aside the laboured subtext about militarism and the whole America policing the world thing, it’s a brilliant epic about love and the indomitability of the human spirit. And they’re all pretty hot, which helps.

But I had another train of thought watching this movie. It reminded me of a guilty secret, and of a violent change in attitude I’ve had toward science fiction in the past few years, and toward Star Trek in particular.

It begins with a confession. As a child, I was a massive Trekkie.

As in, massive.

I could offer many defences of this embarrassing fact, if I cared to: I could point to moments of genre-defying grandeur from Kate Mulgrew, or of Shakespearean gravitas from Patrick Stewart.

Or I could, at some length, discuss the many and varied virtues of Robert Beltran. (Don’t Google him if you’re a fan: these days, he’s depressingly fat.)

The truth is that I was even a fan of Deep Space Nine, impenetrable garbage to all but the most ardent Star Trek fan, because something about that showexcited my imagination.

But, as I have grown older, I have grown to loathe it for reasons that cannot be attributed solely to changing taste or consumption habits. Initially, I couldn’t work out why. Over this past weekend, though, I think I realised what has happened.

At its heart, science fiction is a transgressive genre of fiction: it paints a world of conflict in which the good guys invariably exist on the political and social fringe of the writers’ own societies. The protagonists are normally heroic and somehow displaced.

Star Trek fails this test, and as a result it commits the worst sin of all: it’s boring.

In fact Star Trek, particularly the universe of the later The Next Generation movies and indeed the entire TNG television series that went out in the late eighties and early nineties, is a particularly, peculiarly and almost unbearably saccharine, socialist world, at pains to underscore its rejection of money and the moral good of exploration for its own sake.

Which would all be fine if they weren’t so damned sanctimonious about it.

It is a very peculiarly liberal sort of enlightenment, with elaborate lip service paid to the virtues of education and exploration, particularly in Voyager, but a total absence of coherent belief.

I’m convinced that the Federation uniforms are a sort of twenty-fourth century version of socks with sandals.

The villains of Star Trek, throughout its incarnations, are cartoonishly capitalistic or fascistic figureheads: power-crazed, bloodthirsty, inhumane, obsessed with empire and material wealth; the bankers of the twenty-third century. Even the Borg, who might in a sense be called a communist collective, represent little beside rapacious acquisitiveness.

They’re often even explicitly Right-wing: the Hirogen are dressed as Nazis when they occupy USS Voyager, for God’s sake.

Of course, being the slimy opportunists they are, the Federation regularly gets into bed with the baddies when it suits them.

No explanation is ever given as to how this magical society functions without the good of trade. Instead, the future of human society is depicted as a dreary, bureaucracy-mad, multicultural Hell liberated from the evil clutches of greed. By God is it grating – and insidious!

I don’t know about you, but it’s enough to make me end up rooting for the Ferengi and the Klingons.

In Star Trek IV: The Voyage Home – you know, the “save the whales” epic – which is directed, with typical hubris, by one of its cast, Spock judges time according to pollution levels in the atmosphere. Kirk calls late twentieth-century Earth culture “primitive and paranoid”.

Their search for humpback whales takes them to, of all places, San Francisco. The entire movie, in fact, is a tribute to liberal metropolitan values and environmentalist guilt-mongering. (Its writers clearly absolutely hate America.)

Star Trek isn’t as nakedly and as boringly right-on as movies like Avatar and District 9. It’s a bit worse than that, actually: subtly but continuously suggesting a grim, boring and absurd future in which the good guys are the ones who fill out their forms, don’t interfere with others, wear terrible clothes and believe in absolutely nothing at all.

A preachy, ponderous and preposterous dystopia. No wonder so many Trekkies vote Lib Dem.